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Coresight in JTAG chain

Question asked by Jason Hendrix on May 24, 2016
Latest reply on May 31, 2016 by Yiping Wang

Is the fact that we don't see the coresight modules in our jtag chain a clue as to why we can't "reset_to_debug"?

Hi,

We're trying to bring up the LS1020a on our custom board.  We're having trouble connecting via JTAG (CWTAP via USB) to the bare board in order to flash our RCWs into QSPI flash.  The sequence fails on "reset_to_debug" before we can even load our RCW override value.

We've noticed on the LS1021ATWR dev board, that when you use CCS to get the JTAG chain config, it includes multiple Coresight modules.  On  our board, it only reports the components we told it about when we configured the chain.  Why doesn't our chain show the Coresight modules?  Could this be related in any way to the fact that we can't "reset_to_debug" on our board?

 

Here is the dev board output:

(bin) 83 % ccs::config_chain {ls1020a dap sap2}
(bin) 84 % display ::ccs::get_config_chain
Chain Position 0: LS1020A
Chain Position 1: CoreSight ATB Funnel
Chain Position 2: CoreSight TMC
Chain Position 3: CoreSight TMC
Chain Position 4: CoreSight TMC
Chain Position 5: CoreSight CTI
Chain Position 6: CoreSight CTI
Chain Position 7: CoreSight CTI
Chain Position 8: CoreSight ATB Funnel
Chain Position 9: Cortex-A7
Chain Position 10: Cortex-A7 PMU
Chain Position 11: Cortex-A7
Chain Position 12: Cortex-A7 PMU
Chain Position 13: CoreSight CTI
Chain Position 14: CoreSight CTI
Chain Position 15: Cortex-A7 ETM
Chain Position 16: Cortex-A7 ETM
Chain Position 17: DAP
Chain Position 18: SAP2

 

Here is our board output (we have a Xilinx part in the chain):

% ccs::config_chain {{6 1 0x3f} ls1020a dap sap2}
% display ccs::get_config_chain
Chain Position 0: Generic Device
Chain Position 1: LS1020A
Chain Position 2: DAP
Chain Position 3: SAP2

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